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PubMed2005

Continued gefitinib treatment after disease stabilisation prolongs survival of Japanese patients with non-small-cell lung cancer: Okayama Lung Cancer Study Group experience.

BACKGROUND: This study aimed to investigate the survival outcome of patients with non-small-cell lung cancer (NSCLC) who had obtained disease stabilisation with gefitinib treatment and to clarify the effect of continued treatment with gefitinib on prognosis. PATIENTS AND METHODS: We reviewed the clinical records of 365 Japanese patients with NSCLC who received gefitinib (250 mg/day). RESULTS: Of 324 (89%) patients assessable for response, 147 (45%) obtained disease stabilisation and 71 (22%) patients achieved an objective response. Overall survival in patients obtaining disease stabilisation was significantly longer than in patients with progressive disease (median survival time 12.1 versus 4.4 months; P <0.0001). In patients obtaining disease stabilisation, those who continued gefitinib treatment until disease progression tended to have longer overall and progression-free survival compared with those discontinuing gefitinib treatment (1-year survival rate 52.1% versus 36.6%, P = 0.08; 1-year progression-free survival rate 31.8% versus 5.2%, P = 0.001). Multivariate analysis showed discontinuing gefitinib was an independent risk factor for progression-free survival (hazard ratio 1.66; 95% confidence interval 1.07-2.56; P = 0.022) but not for overall survival. CONCLUSIONS: Our findings indicate the importance of achieving disease stabilisation with gefitinib treatment and continued gefitinib treatment in Japanese patients with disease stabilisation, although further studies are required to confirm these findings.

Adult↗
PubMed2005

Gefitinib in the adjuvant setting: safety results from a phase III study in patients with completely resected non-small cell lung cancer.

Standard therapy for stage I-IIIA non-small cell lung cancer (NSCLC) is surgery, although adjuvant therapies are required to prevent disease recurrence and improve patient survival. This is the first study that planned to administer adjuvant gefitinib (Iressa) 250 mg/day or placebo to randomized patients with completely resected NSCLC (stage IB-IIIA) 4-6 weeks following surgery, for 2 years, until recurrence/withdrawal. However, recruitment was stopped after the randomization of 38 patients, because interstitial lung disease (ILD)-type events were being increasingly reported in Japan in the advanced disease setting. Finally, the trial was halted. Safety data for 38 recruited patients (18 gefitinib and 20 placebo) showed no unexpected adverse drug reactions (ADRs), with the most common being grade 1/2 gastrointestinal and skin disorders in 12 and 16 patients receiving gefitinib and in five and six patients receiving placebo, respectively. Grade 3/4 ADRs occurred in four patients receiving gefitinib and one patient receiving placebo. ILD-type events were reported in one patient receiving gefitinib (concomitantly with other ILD-inducing drugs) who died and two patients receiving placebo. Eight patients receiving gefitinib withdrew due to ADRs compared with three patients receiving placebo. Adverse events associated with surgical complications were reported for six patients receiving gefitinib and four patients receiving placebo. In the adjuvant setting there were no unexpected adverse events observed. Gefitinib had no impact on surgery-related complications when given within 4-6 weeks post-operatively.

Aged↗
PubMedDate not supplied

Gefitinib (Iressa, ZD1839) and tyrosine kinase inhibitors: the wave of the future in cancer therapy.

Targeted therapies are one of the latest innovative trends in cancer therapy. The epidermal growth factor receptor (EGFR) is a target found in high concentrations in several solid tumors including lung, breast, colorectal, and brain. Tyrosine kinase inhibitors, such as gefitinib (Iressa, ZD1839), block the EGFR. As a result, there is inhibition of cellular proliferation, promotion of apoptosis, and inhibition of anti-angiogenesis. Gefitinib has demonstrated significant efficacy in non-small-cell lung cancer (NSCLC), leading to FDA approval for treatment of this refractory disease. Phase 2 trials with gefitinib for platinum refractory NSCLC reported disease response and symptom improvement. Early results of phase 2 studies of gefitinib, combined with standard chemotherapy in colorectal cancer, showed a 75% response rate compared with 55% with standard therapy alone. Gefitinib, combined with flutamide, produced an additive growth inhibition in prostate cancer. A phase 2 trial of gefitinib in first-relapse glioblastoma multiforme demonstrated median overall survival from treatment start of 39.4 weeks compared with 40 weeks with standard chemotherapy. Gefitinib is an oral agent with a mild toxicity profile, and thus, may be an optimal addition to chemotherapeutic regimens for some solid tumors. Gefitinib is potentially a vital and useful weapon in the arsenal of cancer therapies.

Administration, Oral↗
PubMed2006

Aspirin reduces adverse effects of gefitinib.

We measured serum levels of soluble (s) P-selectin and thromboxane B2 (TxB2) in patients with lung cancer treated with gefitinib, and investigated the effect of low-dose aspirin on some adverse effects of gefitinib. The serum levels of sP-selectin and TxB2 increased significantly in all patients who received gefitinib for 2 weeks. Forty patients were recruited, and 28 received gefitinib without low-dose aspirin (Group 1) and 12 were co-administered low-dose aspirin (Group 2). In Group 2, the frequency of adverse events, skin rash and diarrhea was evidently reduced by the low-dose aspirin therapy, despite having shown no remarkable change in gefitinib responsiveness between both groups. In one of the 12 patients in Group 2, aspirin therapy was suspended due to the occurrence of nasal bleeding. Four days after treatment suspension, she developed a skin lesion in her finger. However, the skin lesion improved after re-administration of aspirin without any other medications. After treatment, TxB2 significantly decreased, but not sP-selectin. These results suggest that one of the mechanisms causing gefitinib-related adverse effects depends on platelet activation. Administration of gefitinib with low-dose aspirin to lung cancer patients may prevent the development of gefitinib-related complications.

Adult↗
PubMed2004

Direct inhibition of EGF receptor activation in vascular endothelial cells by gefitinib ('Iressa', ZD1839).

The development of gefitinib ('Iressa', ZD1839) by targeting the EGFR tyrosine kinase is a recent therapeutic highlight. We have reported that gefitinib is antiangiogenic in vitro, as well as in vivo. In this study, we asked if the anti-angiogenic action of gefitinib is due to a direct effect on activation of vascular endothelial cells by EGF. EGF, as well as VEGF, caused pronounced angiogenesis in an avascular area of the mouse cornea, and i.p. administration of gefitinib almost completely blocked the response to EGF, but not to VEGF. Immunohistochemical analysis demonstrated phosphorylation of EGFR by EGF in the neovasculature, and gefitinib markedly reduced this effect. Gefitinib also inhibited downstream activation of ERK 1/2 via EGFR in cultured microvascular endothelial (HMVE) cells. These findings suggest that the anti-angiogenic effect of gefitinib in the vascular endothelial cells of neo-vasculature is partly attributable to direct inhibition of EGFR activation, and that endothelial cells in malignant tumors play a critical role in the cancer therapeutic efficacy of gefitinib.

Antineoplastic Agents↗
PubMed2005

Epidermal growth factor receptor activity determines response of colorectal cancer cells to gefitinib alone and in combination with chemotherapy.

PURPOSE: Up to now, there have been no established predictive markers for response to epidermal growth factor receptor (EGFR/HER1/erbB1) inhibitors alone and in combination with chemotherapy in colorectal cancer. To identify markers that predict response to EGFR-based chemotherapy regimens, we analyzed the response of human colorectal cancer cell lines to the EGFR-tyrosine kinase inhibitor, gefitinib (Iressa, AstraZeneca, Wilmington, DE), as a single agent and in combination with oxaliplatin and 5-fluorouracil (5-FU). EXPERIMENTAL DESIGN: Cell viability was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and crystal violet cell viability assays and analyzed by ANOVA. Apoptosis was measured by flow cytometry, poly(ADP-ribose) polymerase, and caspase 3 cleavage. EGFR protein phosphorylation was detected by Western blotting. RESULTS: Cell lines displaying high constitutive EGFR phosphorylation (a surrogate marker for EGFR activity) were more sensitive to gefitinib. Furthermore, in cell lines exhibiting low constitutive EGFR phosphorylation, an antagonistic interaction between gefitinib and oxaliplatin was observed, whereas in cell lines with high basal EGFR phosphorylation, the interaction was synergistic. In addition, oxaliplatin treatment increased EGFR phosphorylation in those cell lines in which oxaliplatin and gefitinib were synergistic but down-regulated EGFR phosphorylation in those lines in which oxaliplatin and gefitinib were antagonistic. In contrast to oxaliplatin, 5-FU treatment increased EGFR phosphorylation in all cell lines and this correlated with synergistic decreases in cell viability when 5-FU was combined with gefitinib. CONCLUSIONS: These results suggest that phospho-EGFR levels determine the sensitivity of colorectal cancer cells to gefitinib alone and that chemotherapy-mediated changes in phospho-EGFR levels determine the nature of interaction between gefitinib and chemotherapy.

Antineoplastic Agents↗
PubMed2006

Synergistic antitumor activity of epidermal growth factor receptor tyrosine kinase inhibitor gefitinib and IFN-alpha in head and neck cancer cells in vitro and in vivo.

PURPOSE: Epidermal growth factor receptor (EGFR) overexpression has been implicated in the development of head and neck squamous cell carcinomas (HNSCC) and represents a potential therapeutic target for this disease. We have reported previously that growth inhibitory concentrations of IFN-alpha enhance the expression and activity of EGFR and that this effect could represent an escape mechanism to the growth inhibition and apoptotic cell death induced by IFN-alpha. In this study, we investigate whether the combination of IFN-alpha and gefitinib (Iressa, AstraZeneca Pharmaceuticals, Macclesfield, United Kingdom), a selective EGFR tyrosine kinase inhibitor, might have a cooperative antitumor effect on HNSCC-derived cell lines. EXPERIMENTAL DESIGN: The interaction of IFN-alpha and gefitinib was evaluated in vitro on HNSCC-derived cell lines by median drug effect analysis calculating a combination index with CalcuSyn software and in vivo by using HNSCC xenografts in nude mice. The mechanism of gefitinib and IFN-alpha interactions was also studied by analysis of cell cycle kinetics, apoptosis assays, and Western blotting of EGFR signal transduction components. RESULTS: Simultaneous exposure to gefitinib and IFN-alpha produced synergistic antiproliferative and proapoptotic effects compared with single drug treatment. Furthermore, daily treatment of gefitinib (50 mg/kg p.o.) in combination with an IFN-alpha regimen (50,000 units s.c. three times weekly) induced tumor growth delay and increased survival rate on established HNSCC xenografts in nude mice. Moreover, the concomitant treatment with gefitinib suppressed the stimulation of extracellular signal-regulated kinase phosphorylation/activity induced by IFN-alpha both in vitro and in vivo. CONCLUSION: The observed cooperative antitumor effects could be, at least in part, explained by the inhibition exerted by gefitinib of an IFN-alpha-induced EGF-dependent survival pathway, which involves extracellular signal-regulated kinase activation. These results provide a rationale for the clinical evaluation of gefitinib in combination with IFN-alpha in HNSCC.

Animals↗
PubMed2006

Gefitinib inhibits the growth and invasion of urothelial carcinoma cell lines in which Akt and MAPK activation is dependent on constitutive epidermal growth factor receptor activation.

PURPOSE: Abnormally high levels of epidermal growth factor receptor (EGFR) protein are associated with advanced tumor stage/grade. The objective of this study was to evaluate the effects of the specific EGFR tyrosine kinase inhibitor gefitinib on activation of the Akt and mitogen-activated protein kinase (MAPK) pathways in human urothelial cell carcinoma (UCC) cell lines and to identify potential markers of gefitinib responsiveness in biopsy samples of UCC. EXPERIMENTAL DESIGN: Changes in markers of UCC growth and invasion after exposure to gefitinib were studied in six human UCC cell lines expressing various levels of EGFR. The findings were related to activation of Akt and MAPK. We studied the influence of gefitinib on intraepithelial expansion of the responsive 1207 cell line. EGFR, Akt, and MAPK activation was studied by Western blot analysis of a panel of 57 human UCC. RESULTS: Gefitinib had a growth-inhibitory and anti-invasive effect in two of six UCC cell lines (i.e., 647V and 1207). Gefitinib was also able to block the expansion of 1207 at the expense of normal urothelial cells. These effects did not depend on the level of expression of EGFR but they were associated with the down-regulation of MAPK and Akt activity; in 1207 cells, gefitinib activity was associated with p27 up-regulation and p21 and matrix metalloproteinase-9 down-regulation. Similarly, the Akt and MAPK pathways were found to be strongly phosphorylated in association with EGFR activation in a subset of human UCC specimens. CONCLUSIONS: Activation of EGFR, Akt, and MAPK defines a subset of UCC which might provide information for the identification of gefitinib responders.

Cell Division↗
PubMed2006

Optimization of patient selection for gefitinib in non-small cell lung cancer by combined analysis of epidermal growth factor receptor mutation, K-ras mutation, and Akt phosphorylation.

PURPOSE: Mutations in epidermal growth factor receptor (EGFR) are strongly predictive of gefitinib efficacy in non-small-cell lung cancer. However, the presence of EGFR mutant nonresponses and nonmutant responses points out the need for more comprehensive analysis. PATIENTS AND METHODS: For 69 non-small-cell lung cancer patients treated with gefitinib, we have extended our analysis to EGFR gene copy number by fluorescence in situ hybridization, mutations in K-ras, HER2, and exon 20 of EGFR by direct sequencing, and phosphatase and tensin homologue expression by immunohistochemistry, in addition to EGFR exons 18, 19, and 21, and phosphorylations of Akt and extracellular signal-regulated kinase reported previously. RESULTS: EGFR mutation and high gene copy number were associated with better objective response in univariate analysis. However, only gefitinib-sensitive EGFR mutation was independently predictive of both response (P = 0.011) and survival (P = 0.002) in multivariate analysis. No patients with K-ras mutation, including two EGFR mutants, showed response. In EGFR nonmutants, patients with either K-ras mutation or p-Akt overexpression exhibited poor response and time-to-progression whereas patients with high gene copy number tended to have better outcomes in univariate analysis. In multivariate analysis of time-to-progression in EGFR nonmutants, K-ras mutation or p-Akt overexpression was associated with shorter time-to-progression (P = 0.017). No patient with HER2 mutation showed response to gefitinib. Reduced phosphatase and tensin homologue expression was not associated with gefitinib sensitivity. CONCLUSION: Gefitinib-sensitive EGFR mutation is the single most important predictor of gefitinib sensitivity. In addition to EGFR mutation, K-ras mutation and Akt phosphorylation aid in better prediction of gefitinib responsiveness in non-small-cell lung cancer.

Adult↗
PubMed2006

Exon 19 deletion mutations of epidermal growth factor receptor are associated with prolonged survival in non-small cell lung cancer patients treated with gefitinib or erlotinib.

PURPOSE: Somatic mutations in the epidermal growth factor receptor (EGFR) have been detected in patients with non-small cell lung cancer (NSCLC) and are associated with sensitivity to treatment with gefitinib or erlotinib. Our study explored the relationship between the two most common types of somatic EGFR mutations, exon 19 deletions and the L858R point mutation, and outcomes of patients following treatment with gefitinib or erlotinib. EXPERIMENTAL DESIGN: Tumor specimens obtained before treatment with gefitinib or erlotinib were analyzed for EGFR mutations. Patients with exon 19 deletion or L858R mutations were identified. The response rate, time to progression, and overall survival were determined for the two groups. RESULTS: We identified 36 patients with NSCLC and an EGFR mutation who were treated with gefitinib or erlotinib. Patients with an exon 19 deletion had a significantly longer overall survival compared with patients with an L858R mutation (38 versus 17 months; P = 0.04). There were also trends toward higher response rate (73% versus 50%) and improved time to progression (24 versus 10 months) for the patients with an exon 19 deletion, although these were not independently significant in a multivariate analysis. A difference in response rate for patients treated with gefitinib compared with erlotinib was also noted [18 of 23 (78%) versus 3 of 9 (33%); P = 0.04]. No obvious difference in time to progression or overall survival was noted between gefitinib- and erlotinib-treated patients. CONCLUSIONS: Patients with NSCLC and EGFR exon 19 deletions have a longer survival following treatment with gefitinib or erlotinib compared with those with the L858R mutation. Pooling of greater numbers of patients and completion of prospective trials are needed to further define the predictive and prognostic roles of different EGFR mutations with respect to treatment with gefitinib, erlotinib, and other EGFR inhibitors.

Adult↗
PubMed2006

Gefitinib (IRESSA) sensitive lung cancer cell lines show phosphorylation of Akt without ligand stimulation.

BACKGROUND: Phase III trials evaluating the efficacy of gefitinib (IRESSA) in non-small cell lung cancer (NSCLC) lend support to the need for improved patient selection in terms of gefitinib use. Mutation of the epidermal growth factor receptor (EGFR) gene is reported to be associated with clinical responsiveness to gefitinib. However, gefitinib-sensitive and prolonged stable-disease-defined tumors without EGFR gene mutation have also been reported. METHODS: To identify other key factors involved in gefitinib sensitivity, we analyzed the protein expression of molecules within the EGFR family, PI3K-Akt and Ras/MEK/Erk pathways and examined the sensitivity to gefitinib using the MTT cell proliferation assay in 23 lung cancer cell lines. RESULTS: We identified one highly sensitive cell line (PC9), eight cell lines displaying intermediate-sensitivity, and 14 resistant cell lines. Only PC9 and PC14 (intermediate-sensitivity) displayed an EGFR gene mutation including amplification. Eight out of the nine cell lines showing sensitivity had Akt phosphorylation without ligand stimulation, while only three out of the 14 resistant lines displayed this characteristic (P = 0.0059). Furthermore, the ratio of phosphor-Akt/total Akt in sensitive cells was higher than that observed in resistant cells (P = 0.0016). Akt phosphorylation was partially inhibited by gefitinib in all sensitive cell lines. CONCLUSION: These results suggest that Akt phosphorylation without ligand stimulation may play a key signaling role in gefitinib sensitivity, especially intermediate-sensitivity. In addition, expression analyses of the EGFR family, EGFR gene mutation, and FISH (fluorescence in situ hybridization) analyses showed that the phosphorylated state of EGFR and Akt might be a useful clinical marker of Akt activation without ligand stimulation, in addition to EGFR gene mutation and amplification, particularly in adenocarcinomas.

Antineoplastic Agents↗
PubMed2006

Predictive factors for interstitial lung disease, antitumor response, and survival in non-small-cell lung cancer patients treated with gefitinib.

PURPOSE: Interstitial lung disease (ILD) is a serious adverse effect of gefitinib, but its prevalence and risk factors remain largely unknown. We examined the prevalence of and risk factors for gefitinib-induced ILD associated with practical use of the drug in Japanese with non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS: Clinical information was retrospectively assembled for NSCLC patients who started gefitinib treatment at affiliated institutions of the West Japan Thoracic Oncology Group between August 31 and December 31, 2002. Medical records of patients who developed pulmonary infiltrates were reviewed by a central committee of extramural experts for identification of patients with gefitinib-induced ILD. Multivariate logistic or Cox regression analysis was performed to identify independent predictive factors for ILD, antitumor response, and survival. RESULTS: Seventy cases of and 31 deaths from gefitinib-induced ILD were identified among 1,976 consecutively treated patients at 84 institutions, corresponding to a prevalence of 3.5% and mortality of 1.6%. Gefitinib-induced ILD was significantly associated with male sex, a history of smoking, and coincidence of interstitial pneumonia (odds ratios = 3.10, 4.79, and 2.89, respectively). Predictive factors for response were female sex, no history of smoking, adenocarcinoma histology, metastatic disease, and good performance status (PS), whereas predictive factors for survival were female sex, no history of smoking, adenocarcinoma histology, nonmetastatic disease, good PS, and previous chest surgery. CONCLUSION: ILD is a serious adverse effect of gefitinib in the clinical setting that cannot be ignored. However, patient selection based on sex and smoking history can minimize ILD risk and maximize the clinical benefit of gefitinib.

Adult↗
PubMed2005

Gefitinib in non-small cell lung cancer.

Gefitinib (Iressa), an orally-active tyrosine kinase inhibitor of the epidermal growth factor receptor (EGFR), is the first approved molecular-targeted drug for the management of patients with advanced non-small cell lung cancer (NSCLC). Two Phase II trials (IDEAL [Iressa Dose Evaluation in Advanced Lung Cancer]-1 and -2), evaluated the efficacy of gefitinib in advanced NSCLC patients who received < or = 2 (IDEAL1) or > or = 2 (IDEAL2) previous chemotherapy regimens. The response rate and disease control rate in IDEAL1 and -2 was 18/12% and 54/42%, respectively. The median survival time and one-year survival rate in both studies were approximately 7 months and 30%, respectively. As gefitinib has demonstrated antitumour activity and an acceptable tolerability profile not typically associated with cytotoxic adverse events, such as hematological toxicities, combinations with cytotoxic drugs have been evaluated. Disappointingly, in chemotherapy-naive patients with advanced NSCLC, gefitinib 250 and 500 mg/day combined with platinum-based chemotherapy (gemcitabine/cisplatin or paclitaxel/carboplatin) did not produce prolonged survival, compared with chemotherapy alone in two large, randomised, placebo-controlled, multi-centre Phase III trials (INTACT [Iressa NSCLC Trial Assessing Combination Treatment]-1 and -2). Furthermore, in a recent randomised, placebo-controlled, Phase III trial (ISEL: IRESSA Survival Evaluation in Lung cancer), gefitinib failed to prolong survival compared with placebo in patients with advanced NSCLC who had failed one or more lines of chemotherapy. Subgroup analysis of ISEL suggested improved survival in patients of Asian origin and non-smokers. In addition, subset analyses of IDEAL and several retrospective studies have indicated that female gender, adenocarcinoma histology (especially bronchial alveolar carcinoma), non-smoker status and Asian ethnicity are factors which predict to response to gefitinib. Two types of somatic mutation clustered around the ATP binding pocket in the tyrosine kinase domain of the EGFR gene have been reported as possible surrogate biological markers for predicting response to gefitinib. Appropriate patient selection by clinical characteristics or genetical information is needed, both for future clinical trials of gefitinib and its routine use in the clinic among patients with advanced NSCLC.

Animals↗
PubMed2004

Insulin-like growth factor-I receptor signalling and acquired resistance to gefitinib (ZD1839; Iressa) in human breast and prostate cancer cells.

De novo and acquired resistance to the anti-tumour drug gefitinib (ZD1839; Iressa), a specific epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) has been reported. We have determined whether signalling through the IGF-I receptor (IGF-1R) pathway plays a role in the gefitinib-acquired resistance phenotype. Continuous exposure of EGFR-positive MCF-7-derived tamoxifen resistant breast cancer cells (TAM-R) to 1 microM gefitinib resulted in a sustained growth inhibition (90%) for 4 months before the surviving cells resumed proliferation. A stable gefitinib-resistant subline (TAM/TKI-R) was established after a further 2 months and this showed no detectable basal phosphorylated EGFR activity. Compared with the parental TAM-R cells, the TAM/ TKI-R cells demonstrated (a) elevated levels of activated IGF-1R, AKT and protein kinase C (PKC)delta, (b) an increased sensitivity to growth inhibition by the IGF-1R TKI AG1024 and (c) an increased migratory capacity that was reduced by AG1024 treatment. Similarly, the EGFR-positive androgen-independent human prostate cancer cell line DU145 was also continuously challenged with 1 microM gefitinib and, although substantial growth inhibition (60%) was seen initially, a gefitinib-resistant variant (DU145/TKI-R) developed after 3 months. Like their breast cancer counterparts, the DU145/TKI-R cells showed increases in the levels of components of the IGF-1R signalling pathway and an elevated sensitivity to growth inhibition by AG1024 compared with the parent DU145 cell line. Additionally, DU145/TKI-R cell migration was also decreased by this inhibitor. We have therefore concluded that in breast and prostate cancer cells acquired resistance to gefitinib is associated with increased signalling via the IGF-1R pathway, which also plays a role in the invasive capacity of the gefitinib-resistant phenotype.

Antineoplastic Agents↗
PubMed2005

Single-dose clinical pharmacokinetic studies of gefitinib.

BACKGROUND: The objective of the five clinical studies presented in this article was to investigate the single-dose pharmacokinetics of gefitinib (IRESSA, ZD1839), an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, in healthy volunteers and patients with advanced cancer. METHODS: Studies 1 and 3-5 recruited healthy male volunteers aged 18-65 years; study 2 recruited male or female patients aged>or=18 years with any solid malignant tumour expressing EGFR and refractory to standard therapy. Gefitinib administration was as follows: study 1 (bioavailability in healthy volunteers; n=12)--intravenous infusion of 50 or 100 mg followed by a single oral dose of 250 mg; study 2 (bioavailability in cancer patients; n=19)--intravenous infusion of 50 mg followed by a single oral dose of 250 mg; study 3 (intrasubject variability; n=24)--two single oral doses of 250 mg; study 4 (dose-proportionality; n=15)--three single oral doses of 50-500 mg; study 5 (effect of food; n=26)--two single doses of 250 mg under either fed or fasted conditions. In all studies, venous blood samples for determination of gefitinib plasma concentrations were collected at predetermined intervals. Plasma concentrations of gefitinib were measured using liquid-liquid extraction after basification followed by high-performance liquid chromatography with tandem mass spectrometric detection. Appropriate pharmacokinetic parameters were determined by noncompartmental methods. RESULTS: Study 1: Oral bioavailability of a gefitinib 250 mg dose was 57% in healthy volunteers. Absorption was moderately slow, with geometric mean (gmean) peak plasma concentration (Cmax) of 85 ng/mL (range 43.5-110 ng/mL) reached 5 hours following an oral dose of 250 mg. Study 2: Oral bioavailability of a gefitinib 250 mg dose was 59% in patients. Absorption was again moderately slow, with gmean Cmax of 159 ng/mL (range 48.7-324 ng/mL) typically reached 3 hours (range 1-8 hours) following an oral dose of 250 mg. Study 3: Area under the plasma concentration-time curve from time zero to infinity (AUCinfinity) and Cmax were variable--up to 15-fold between subjects and 2-fold within an individual. Study 4: AUCinfinity and Cmax increased with dose across the range of 50-500 mg, and increased dose-proportionally up to 250 mg. Study 5: Small, clinically insignificant increases in AUCinfinity and Cmax were seen in the presence of food (32% and 37%, respectively). CONCLUSIONS: The gefitinib 250 mg tablet is orally bioavailable in both healthy volunteers and cancer patients; bioavailability is independent of dose and unaffected by food to any clinically significant extent. Gefitinib undergoes rapid plasma clearance and has an extensive volume of distribution, resulting in a pharmacokinetic profile supportive of a once-daily dosage regimen.

Administration, Oral↗
PubMed2004

[Transient liver injury caused by gefitinib].

Gefitinib blocks epidermal growth factor receptor autophosphorylation and subsequently the signal transduction pathways implicated in proliferation, metastasis, invasion, and angiogenesis. Reported adverse reactions to gefitinib include liver injury that is not fully understood. Liver injury was observed in 5 (12.2%) of 41 patients with non-small cell lung cancer who received gefinitib monotherapy. Onset of liver injury was seen between 28 and 56 days after initiation of administration. Two patients had Grade 2 liver injury and 3 patients, Grade 3. In 4 patients, liver injury was temporary, lasting during a period of continuous gefitinib administration. In another patient, gefitinib was discontinued because of the onset of liver injury, which improved when gefitinib administration was restarted. Gefitinib is necessary in most patients whose lung cancer is refractory to cytotoxic chemotherapy, because no other treatment regimens are available at present. The rate of liver injury in cases treated with gefitinib is high, and so it is necessary to observe liver function carefully, but the liver injury due to this drug is often transient. However, the use of gefitinib in many cases appears to be a necessity.

Adult↗
PubMed2006

Evaluation of the epidermal growth factor receptor gene mutation and copy number in non-small cell lung cancer with gefitinib therapy.

Several studies have suggested that epidermal growth factor receptor (EGFR) gene mutation, EGFR gene amplification, and some other biomarkers may be predictors of gefitinib sensitivity. We analyzed EGFR mutation and EGFR copy number in 22 gefitinib-treated non-small cell lung cancer (NSCLC) cases and their relation to the survival of patients. We also studied 143 gefitinib-naïve Japanese NSCLC cases. The erbB2 copy number was also studied in 59 gefitinib-naïve NSCLC cases. In gefitinib-treated patients, the presence of EGFR mutation was associated with a higher response rate to gefitinib and a longer overall survival, but the increased EGFR gene copy number was not. In gefitinib-naïve cases, EGFR mutation but not EGFR gene copy number was significantly correlated with gender, pathological subtypes, and smoking status. The erbB2 copy number was not significantly correlated with the EGFR mutation or EGFR copy number in 59 cases. In conclusion, EGFR mutation was a better predictor of clinical outcome in gefitinib-treated patients than the EGFR gene copy number.

Adenocarcinoma↗
PubMed2025

Exosomal proteomics reveals fatty acid metabolism linked to gefitinib resistance in non-small cell lung cancer.

Exosomes play a crucial role in the transmission of drug resistance in tumors. However, the mechanism of exosomes-mediated transmission in non-small cell lung cancer (NSCLC) under gefitinib treatment remains limited. In this work, we demonstrated that exosomes derived from HCC827/GR cells (drug-resistant) enhanced the survivability of HCC827 cells (drug-sensitive) under treatment with gefitinib. A total of 157 shared upregulated proteins between exosomes and their parent cells were identified in the comparison of the gefitinib-resistant groups versus the gefitinib-sensitive groups. Notably, 69 of these shared proteins are enzymes, and many of them were enriched in pathways related to fatty acid metabolism. Among these enzymes involved in fatty acid metabolism, ACC1 exhibited the highest fold change in upregulated expression in both drug-resistant groups (exosomes and cells). Moreover, the expression of ACC1 was upregulated in gefitinib-sensitive cells after uptake of exosomes from gefitinib-resistant cells. The role of ACC1 in enhancing the survival of HCC827/GR cells under gefitinib treatment was demonstrated using an inhibitor and siRNA-mediated knockdown. Specifically, the upregulated ACC1 stabilized fatty acid oxidation and reactive oxygen species levels in HCC827/GR cells, thereby maintaining cellular metabolic homeostasis. Collectively, this work reveals the transmission of drug resistance in NSCLC via exosomes that carry the ACC1 protein.

Humans↗